A salesman was saved by firefighters after his falling van got caught in the wreckage of the bridge, while his companion plunged to his death.
At least 38 people died and 15 were injured when the bridge fell.
Between 10 and 20 people may still be missing under the rubble, Genoa's chief prosecutor has told reporters.
Francesco Cozzi told Reuters news agency by telephone that this was the working hypothesis based on information from relatives who had not heard from family members and the number of vehicles thought to have been on the bridge when it went down.
Dozens of vehicles dropped when a huge tower and a section of the Morandi bridge measuring about 200m (656ft) collapsed about 45m on to railway lines, a river and a warehouse.
The Morandi, which was built in the 1960s, stands on the A10 toll motorway, Italy's main land corridor with France.
Infrastructure across Italy will be double-checked in the aftermath of the disaster, the government has promised.
The bridge's operator, Autostrade per l'Italia, is under mounting pressure from politicians and share traders, with the government threatening to terminate contracts and impose heavy fines.
At one point in morning trading, shares in Autostrade's holding company, Atlantia, fell by as much as 25%.